The pineal gland is an organ whose potential impact on the body is considerable, but whose true importance is still undetermined. The long-term objectives of this proposal are to understand the possible role of the pineal gland in body temperature regulation and adaptation to stress. Previous work has shown that rats are protected from hypothermia during restrained cold exposure by alterations in diet and by adaptation to restraint. One specific goal is to determine if the pineal gland is involved in this protection by observing if pinealectomized rats are also protected by these two factors. The second goal of this research is to record single unit activity in the pineal gland to determine if neurons exist which are sensitive to temperature changes in the pineal gland, preoptic anterior hypothalamus or the skin. If true, then such a finding would enhance the widely held notion that the pineal gland is a thermoregulatory organ. The pineal gland has been linked to many disorders such as cancer, mental illness and hypertension. Thus, if this proposal can add to the basic understanding of pineal function and if it can demonstrate that diet can infuence pineal performance, then it may be of considerable worth for the clinical sciences.